Re: 2.4.8-pre1 and dbench -20% throughput

From: Rik van Riel (
Date: Fri Jul 27 2001 - 16:42:26 EST

On Fri, 27 Jul 2001, Roger Larsson wrote:

> But "dbench 32" (on my 256 MB box) results has are the most interesting:
> 2.4.0 gave 33 MB/s
> 2.4.8-pre1 gives 26.1 MB/s (-21%)
> Do we now throw away pages that would be reused?

Yes. This is pretty much expected behaviour with the use-once
patch, both as it is currently implemented and how it works
in principle.

This is because the use-once strategy protects the working
set from streaming IO in a better way than before. One of the
consequences of this is that streaming IO pages get less of a
chance to be reused before they're evicted.

Database systems usually have a history of recently evicted
pages so they can promote these quick-evicted pages to the
list of more frequently used pages when it's faulted in again.



Executive summary of a recent Microsoft press release:
   "we are concerned about the GNU General Public License (GPL)"

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to More majordomo info at Please read the FAQ at

This archive was generated by hypermail 2b29 : Tue Jul 31 2001 - 21:00:35 EST